Vaults with submersible equipment are used in a variety of applications. These vaults are often kept below ground. These vaults often include equipment that is submerged in water. Examples of vaults with submersible equipment include pump stations, wet wells, digesters, grease interceptors, storm pollution control structures, or other below-ground holding vessel, vault, or tank. In many cases, the water is waste water or other water with contaminants, such as, suspended particulates, waste matter, or pollutants. Over time, semi-solid or solid contaminants, such as sludge and debris can build up, especially along the bottom or floor of the vaults. These contaminants can damage submerged pumps, pollution control structures, and other equipment. These contaminants can also damage the walls and floor of the vaults. Vaults, especially those with submersible equipment, must therefore be cleaned from time to time.
Various apparatuses and methods have been used to clean vaults with submerged equipment. Many of these methods and devices are used in combination with vacuum trucks with storage tanks and cleaning equipment, such as Vactor Trucks®. Vactor Trucks® include a storage tank coupled with equipment and a hose. Waste water and other materials can be suctioned through the hose and into the storage tank of the Vactor Truck®. In addition, a Vactor Truck® can often shoot waste water out of the tank and hose. In some cases, a Vactor Truck® can alternate sucking in and shooting out waste water. As noted above, a Vactor Truck® may be used with other apparatus and methods to clean a vault with submerged equipment.
Many current methods of cleaning and maintaining a vault require a person to enter the vault. In at least some environments, entering a vault can be dangerous, even life-endangering. For example, a vault that is part of a sewer system may have standing water that presents a drowning hazard. Further, the floor of a vault may have slippery material that makes walking within the vault hazardous. Submerged equipment and pipes may compromise maneuverability. Sewer system vaults also may contain hydrogen sulfide (H2S), a flammable and poisonous gas. The mixture of hydrogen sulfide gas and air can be explosive. Other dangerous gases, such as methane, may also be present. Oxygen levels may be low. Therefore, for human safety, it may be required to utilize safety procedures and equipment for confined spaces when entering a vault that is part of a sewer system. For example, sometimes an attendant, who remains outside of the vault, is required. For a human being entering a sewer system vault, a harness and other protective equipment may be required.
In designing apparatuses and methods for cleaning and maintaining vaults with standing water and equipment, various design considerations may be considered.
One possible design consideration is the extent to which a human being is required to enter the vault as part of the cleaning and maintenance. The entry of human beings into these vaults creates a risk of injury.
Another design consideration is the simplicity of the apparatus or method for cleaning and maintenance. For example, having a human being enter a vault takes time and may not be efficient. For example, sometimes a second human being must often be on site for safety reasons or to operate a hoist to retrieve the first human being from the vault.
Another possible design consideration is the extent to which an apparatus and method requires the insertion and manipulation of a vacuum hose in the vault interior for cleaning purposes. Manipulating a vacuum hose inside a vault is a cumbersome process, especially considering that floats, transducers, power cables, and other articles may be in the way. Thus, another possible design consideration is the extent to which the above equipment is needed to clean and maintain a vault.